My summary

Born as twins, marry each other
They have simple and comfortable living, huge bodies, Kalpavrikshas and they almost always die into becoming dev since they are always in such peace throughout their lives.
They do not have dharm and possibility of going to moksh
Live in 86 = 50 Akarm Bhumi + 36 Antar dwips throughout all time and in few Aras of 15 karm Bhumi as well

AI Notes

1. Core Definition

The Twin Phenomenon: A Yugalik is always born as a pair of twins consisting of one boy and one girl.
Life Companionship: They remain together for their entire lifespan. They share their home, food, and daily life.
Transition of Relationship: In the early phase of their long lives, they live as companion siblings. In the latter part of their life, their relationship shifts into a married-like pair for procreation.
Generational Cycle: They give birth to exactly one more set of Yugalik twins near the very end of their life, ensuring the continuation of their generation.

2. Cosmic Timeline & Environment

According to the Jain time-cycle (Kaalchakra), time is an infinite, repeating wheel split into two halves: Avasarpini (descending/regressive) and Utsarpini (ascending/progressive). Yugaliks exist exclusively in the eras known as Bhogbhumi (the land of enjoyment/contentment).

Existence Across the Eras (Aras)

Within the regressive Avasarpini half-cycle, their existence scales across the first three epochs:

1st Era (Suṣama-suṣamā): Peak Yugalik period. Utmost natural happiness, zero sorrow.
2nd Era (Suṣamā): Moderate happiness, no sorrow. Yugalik populations thrive naturally.
3rd Era (Suṣama-duḥṣamā): Transition period. Natural happiness begins to decrease, and slight sorrow introduces itself. The Yugalik lifestyle completely fades away by the end of this era.
4th, 5th & 6th Eras: Completely absent. In our current 5th Era (Duḥṣamā), Yugaliks do not exist. We live in Karmabhumi (the land of action/labor).

3. Physical & Lifestyle Characteristics

Attribute	Description
Lifespan	Exceptionally long, measured in Palyopamas (cosmic units of time) or lakhs of years, depending on the specific era.
Physical Stature	Described in scriptures as extraordinarily tall, symmetrical, beautiful, and naturally robust.
Health	Free from complex physiological diseases, severe physical pain, or mental anxieties.
The Kalpavrikshas	They do not farm, cook, or build homes. All physical needs—food, clothing, shelter, light, and ornaments—are effortlessly provided by 10 types of wish-fulfilling trees called Kalpavrikshas.

4. Spiritual and Behavioral Nature

Mild Passions (Kashayas): Yugaliks possess highly refined, gentle mental states. Their core negative passions—anger (Krodha), pride (Maana), deceit (Maya), and greed (Lobha)—are naturally minimal.
Lack of Formal Dharma: Structured spiritual paths, vows (Vratas), monastic orders, or Tirthankars do not exist during the Bhogbhumi eras because life is naturally peaceful and unburdened by societal complexity.
Karmic Footprint: Because their daily life lacks violence, intense greed, or malice, they generate very mild, auspicious karma.
Post-Life Destination: At the end of their long lifespans, both twins pass away simultaneously (often triggered by a simple sneeze or yawn) and are traditionally reborn in the heavenly realms (Deva-gati).

5. The Transition out of the Yugalik Era

As the 3rd era drew to a close, the Kalpavrikshas began to fade, resources diminished, and human passions rose. This led to conflict, marking the end of the Yugalik way of life.

The Rise of Karmabhumi: To teach humanity how to survive without the wish-fulfilling trees, Bhagwan Rishabhanath (Adinath)—the 1st Tirthankar of our cycle—stepped forward. He established the social structures we know today, teaching the arts of agriculture, writing, law, marriage, and warfare, transitioning the world from Bhogbhumi to Karmabhumi.